Prior art vehicles typically include an internal combustion engine that is contained in an engine compartment in the front or rear of the vehicle body. The engine is fueled by a liquid, such as gasoline or diesel fuel, which is typically stored in a tank toward the rear of the vehicle. The engine drives the vehicle by applying torque to road wheels through a mechanical transmission.
Alternative vehicle fuels, such as compressed hydrogen and natural gas, have lower specific thermal energy per unit volume than liquid fuels like gasoline and diesel fuel, i.e., they have relatively low energy density. Accordingly, an alternative fuel vehicle may have a significantly reduced driving range before refueling than a conventional fuel vehicle with identical fuel storage capacity. It is therefore desirable for alternative fuel vehicles to accommodate larger fuel storage tanks than those found in conventional fuel vehicles.
It is also desirable to place alternative fuel storage tanks in a protected location within the vehicle chassis. Accordingly, alternative fuel storage tanks are typically placed between the rear wheels of the vehicle. However, packaging space between the rear wheels is limited, which, in turn, limits the size of the tanks and the vehicle travel range between refuelings.